I haven't tried this on a Buffalo, I have flashed the mainline build on a Buffalo. With the mainline ones, there was never a firmware specific to that model, you could use any of them. And the TomatoVPN should fit on the 4MB Flash. SgtPepperKSU has his own thread on this specific firmware, maybe you can check in there to confirm the Buffalo accepts the TomatoVPN firmware.http://www.linksysinfo.org/forums/showthread.php?t=59416